US2860189A - Automatic switching system with reduced internal blocking - Google Patents

Automatic switching system with reduced internal blocking Download PDF

Info

Publication number
US2860189A
US2860189A US452421A US45242154A US2860189A US 2860189 A US2860189 A US 2860189A US 452421 A US452421 A US 452421A US 45242154 A US45242154 A US 45242154A US 2860189 A US2860189 A US 2860189A
Authority
US
United States
Prior art keywords
switches
subscribers
digits
numbers
mixing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US452421A
Other languages
English (en)
Inventor
Roelof M M Oberman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nederlanden Staat
Original Assignee
Nederlanden Staat
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nederlanden Staat filed Critical Nederlanden Staat
Application granted granted Critical
Publication of US2860189A publication Critical patent/US2860189A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/42—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker

Definitions

  • the invention relates to a control equipment for an automatic telecommunication system. More particularly, it deals with an automatic telegraph or telephone system arranged as a link system.
  • the well-known systems of this kind all have a so-called line-link frame consisting of two switching stages, the so-called A-stage and B-stage, also called primary and secondary stage, respectively.
  • A-stage and B-stage also called primary and secondary stage, respectively.
  • the primary or A-stage consists of smaller switching units, which with the same number capacity of the line-link frame requires an increase of the switching units in the secondary or B-stage.
  • Small switching units in the A-stage of the line-link frame means small groups of links via which the group of subscribers lines connected to such switching units can be reached. This results in the fact that the subscribers to be connected must be carefully grouped according to their trafiic and that in the case of traific fluctuations difiiculties may be expected.
  • This mixing method is primitive, because not more than two different groups can be obtained. A more comprehensive mixing can only be obtained by involving not only the last two, but all three digits in the mixing process. Relatively simple considerations already show that in this mixing method the complications become extremely great, whereas on the other hand the advantage is in certain respects only limited.
  • a more effective mixing method which may involve only the last two figures of a subscribers number, it necessary, can generally be obtained by the application of any arithmetic operation on the digits involved in the mixing process, which yields an even distribution of these digits over the relevant series of numbers.
  • Fig. 1 shows an electrical wiring diagram of the first and end sections of a binary adder as used in the control equipment for an automatic communication system according to this invention
  • Fig. 2 shows a modification of the binary adder wiring diagram shown in Fig. 1 using differential relays in all adding sections except the first;
  • Fig. 3 shows a block-diagram of four sections of a binary adder similar to that shown in Figs. 1 or 2;
  • Fig. 4 shows an electrical wiring diagram of a contacttree of contacts of relays R up to R of an adder as shown in the previous figures, which contacts are connected in such a way that the output leads i-i-il give the decimal result of the binary addition;
  • Fig. 5 shows the drawing symbol used for the contact tree in Fig. 4;
  • Fig. 6 shows a wiring diagram of part or a marker circuit for a line link frame adapted according to this invention and showing the register-relays 11-11; and E --E for the tenth and unit digits of the desired number adding and subtracting devices (four pieces) for addition and subtraction of said tenth and unit digit, and contact trees for the register-relays and the sum of the difference relays of the adders and subtractors providing ways between busy test contacts of the automatic switches and the testing device in the common controi equipment; and
  • Figs. 7 and 8 are tables showing by way of example how groups of twenty numbers of a hundred group can be combined in various ways using simple arithmetic methods corresponding to the arrangement of the outlet contacts of multicontact switches.
  • Table i (Fig. 7) wherein the numbers ll to 00, constituting a complete hundred group, are arranged in 10 columns and 10 rows of 10. If to the last digit of each of the numbers a number is added, or if a number is subtracted from it, which number is equal to the number of the relevant row, or to the first digit of the relevant number, the original numbers, arranged in rows sloping by 45 degrees (downward to the right for subtraction and downward to the left for addition, will have the same last digit after the operation.
  • the arithmetic series is in this case the row of the natural numbers from i to 0 (iii). Consequently, the rows shown also indicate the grouping in connection with the mixing method.
  • Table II shows in this mixing method a next step consisting in the application of the arithmetic series obtained from the natural series of the numbers by duplication.
  • the numbers exceeding 10 in the series need only to be indicated by their units digits.
  • the series of addends and subtrahends may further be continued.
  • the following series would have to be the threefold of the series of natural numbers. This is quite possible, but as will result later from the practical embodiment it is less practical than the series which is the quadruple of the original series.
  • the quintuple gives no result.
  • the series of numbers which represent the sextuple, septuple, octuple and nonuple of the original series given a result corresponding with that of the natural series of numbers, the double, triple and quadruple of this series, in which case addition and subtraction must be interchanged however.
  • this method provides for practical purposes a sufiicient number of different mixings.
  • the addition of the first digits of the two numbers yields, as a first binary digit of the sum, a digit having a value of 1, if one of the two binary digits has a value of 1. If both the binary digits to be added amount to 1, a carryover must be effected to the adding device for the second binary digits of the numbers, no digit being recorded on the first place.
  • R denote energization of the windings.
  • the sections of a binary adder shown in Fig. 1 are the first and the nth, all sections, not shown have the same the second section.
  • Fig. 2 The diagram shown in Fig. 2 is a variation of that givenin Fig. 1. Its operation is the same (see Tables III and IV above).
  • the use of differential relays in all sections except the first) results in the use of about half of the number of contacts on the relays on which the bits to be added are stored in the different sections of the adder. 1
  • Fig. 3 An arrangement by means of which an addition or a subtraction can be performed will be represented symbolically by Fig. 3.
  • the squares in Fig. 3, which are marked with a contain a sectional diagram of. an adder'as shown in Fig. 1 or 2 except the sum relay R, which is shown in Fig. 3 for reasons of simplicity as a one winding relay.
  • the tens digit of the total has to. be omitted and the unit digit has to be converted into a decimal representation because it must be used to find back a certain group of links.
  • This can be done in a well-known way by means of a contact tree having 21 outlets, of which those having value indications of 11 and higher are connected to those having value indications of l to 0
  • Such a contact tree will consist of change-over contacts, one forthe top, the other 19 being distributed over 4 relays, as it is done by way of example in Fig. 4.
  • the connections of 20outlets to 10 outlets having values of 1 to 0 (10) has also been indicated in this figure.
  • This standard circuit. will symbolically be represented by Fig. 5 in the further explanation. In the case of a ten-point contact tree being connected to five outlets having values of l to 5, indications of 1 and 5 are placed in the symbol shown in Fig. 5, instead of 1 to 0.
  • the line-link frame receives the whole number of the subscriber to be called and that of the calling subscriberj from the register. If e. g. mixing is only applied in a hundred group of subscribers, the last two digits of both subscribers numbers are submitted to one or more of the above-mentioned operations. If, consequently, a subscriber has e. g. 6 possible paths at his disposal, there must be provided 6 mixing patterns.
  • the easiest possibilities consist in taking: (a) the normal order of sequence of the last two digits; (b) the inverse order of the last two digits; (0) four sets of paths determined by the sum or the difference of the last, or last but one, digit and the series of the natural numbers or the double of them.
  • Fig. 6 shows that part of a marker of a cross-bar switching system, which is necessary to locate the various possible ways via which a subscriber in a mixed group can be found.
  • the example shown in Fig. 6 relates to a cross-bar system having 20-point switches in the A- or primary stage of the subscribers line link frame. Without any departure from the original invention, this number of outlets of the switches in the A-stage of the switching system may be varied.
  • a subscriber can be reached via 6 different links of the A- and B-stage (primary and secondary switches) of the subscriber line link frame, there must be provided 6 5 test links between the A-switches serving each group of hundred subscribers and the marker.
  • These last mentioned test links are shown entering the marker (Fig. 6) at the right hand side. They are marked with to busy contacts: of various hundreds.
  • test wires between the busy contacts of the various crossbar switches in the A-stage of a subscribers line link frame are connected to bridges of crossbar switches BB, which are shown in Fig. 6 with the symbol.
  • a crossbar switch having 10 bridges possessing 20 positions each, can be used to establish the desired connection between the busy contacts of thelinks be tween the A- and B-stage of the line-link irameand the marker.
  • the fact is that such a crossbar switch has 10 2 l0 positions each having 5 contacts. Even four thousand subscribers might be directly served by such a switch.
  • the crossbar switch BB has to be positioned according to the thousands and hundreds digit of the desired subscribers number.
  • These contact trees which are already described in detail in Fig. 4, connect the 6 usable test links out of the group of 30 possible test links serving the group of A-switches via which the desired subscriber can be reached, with a testing device, which can, in connection with other known apparatus, determine the A-switch via which the desired connection will be built up.
  • This testing of links is a known technique in crossbar systems.
  • FIG. 6 shows two groups of 4 register relays of the Marker T up to T and E up to E As soon as the marker is seized by a sender, all information temporarily stored in the sender is trans ferred from the sender to the marker. This information contains amongst others the complete numbers of called and calling subscribers.
  • FIG. 7 shows only the register relays for storing the last two digits of one of these subscriber numbers.
  • a marker will amongst other means consist of two of the calculating circuits shown in Fig. 6.
  • the information is e. g. transferred from the sender to the marker by means of groups of 4 wires, from which groups only two are shown, numbered 10 up to 13 and 14 up to 17. If one or more of such wires are connected to ground in the sender, the relevant relay (T T E E in the marker will operate and close via a contact (t t or e 2 a holding circuit. Contacts of said relays T T and E E, are connected in the adding circuits A and A the subtracting circuits S and S and the contact trees T and E.
  • the adding and subtracting circuits A A S and S are symbolically shown in Fig. 6.
  • the actual circuits are e. g. shown in Figs. 1 and 2, so that there is no need to give here a further explanation.
  • the ways of adding and subtracting the two digits involved has already been clarified by means of Figs. 7 and 8.
  • the results of these adding and subtracting processes are stored on four groups of relays, named S R S 11 R A R By means of contacts of each of these four groups of relays a contact tree is formed along the lines described for Fig. 4.
  • the marker After receiving the necessary digits from the sender, the marker performs the adding and subtracting processes on the last two digits of a subscriber number, with the result that the busy contacts of the six switches in the A- or primary stage of the subscribers line link frame via which the desired subscriber can be reached, are connected to the link testing device in the marker.
  • testing arrangement Any arrangement capable of testing the busy condition of the links between the A- and the B-switches, at the same time with the busy condition of the other groups of links provided between the outgoing and the incoming B-switches of the line-link frame, may serve.
  • a very important point in the described mixing of the connection of the A-switches of the line-link frame is that it automatically enables to obtain a division of the subscribers into groups which can be served by separately working control circuits, as is also described in the Oberman U. S. Patent application Serial No. 430,340, filed May 17, 1954.
  • the control method as it is described in the said patent application has the advantage that in the case of control circuit trouble, a numerical group of subscribers is not put out of service, but that the traffic capacity of a certain group decreases. This is obtained at the cost of a more complicated and therefore more expensive multiple of the switches of the A-stage of the line-link frame.
  • the invention described above requires such a multiple, and yields then automatically the independent setting of the various (mixing) groups, with the attendant advantage of a reduction of the number of switches required in the A-stage.
  • This busy selector may be connected to the desired hundred group of subscribers via relays or similar devices having a large number of contacts (30 in the case of 6 outlets per subscriber and 20- point bridges of the switches in the desired A-stage).
  • the converting method described above, which required an addition and/or a subtraction, is embodied in the fixed wiring of the busy test selector. It depends on the extensiveness of the desired mixing and the cost of the relay converting apparatus against that of the selector or the part of the required crossbar switch which serves as a busy test selector, which method is to be preferred as the most economic one. In all probability the relay method will deserve the preference.
  • Any self contained good grouping may be used in cooperation with such a switch, as it only depends on the wiring via which links a specified numerical line can be reached.
  • An automatic switching system having a plurality of numbered terminals any one of which may be connected to any other through a given plurality of multi-contact switches and connections by calling its corresponding number, and means for increasing the degree of freedom of connections through said switches and said connections between any calling and a called numbered terminal, said means comprising: means for storing the called number corresponding to a called terminal, separate means for converting the stored number into a corresponding number in each of a plurality of differently ordered corresponding systems of numbers, means for connecting the contacts of said switches in a multipled group in orders corresponding to each of said systems, means controlled by the storing means and said separate converting means for connecting the contacts of said switches in accordance with each regular numerical system corresponding to said called number, and means for busy testing'said connected contacts corresponding to said called number for determining a free connection to said called terminal.
  • a system according to claim 1 wherein said separate means for converting said stored number comprises a calculator circuit.
  • a system according to claim 2 wherein said calculator comprises an adder.
  • a system according to claim 2 wherein said calculator comprises both an adder and a subtractor.
  • said means for connecting said contacts comprises contact trees cor responding to each of said storing and separate converting means.
  • each link circuit comprising primary and second a-ry groups of multi-cont-act switches and connections between said switches, the improvement comprising: means for connecting the outlet contact of a group of primary switches in a predetermined non-parallel order, means for receiving signals corresponding to each said outlet contact, and means for converting said signals to other signals corresponding to connections of another said outlet contact whereby internal blocking is materially reduced in said exchange.
  • a system according to claim 9 wherein said means for receiving said signals comprises registering relays.
  • a system according to claim 9 wherein said means 15 for converting said signals comprises a calculator circuit.
  • a system according to claim 12 wherein said calculator comprises an adder.
  • a system according to claim 12 wherein said calculator comprises both an adder and a subtractor.
  • a system according to claim 12 wherein said means for converting said signal includes contact trees for setting up said connections, said trees being controlled by said calculator.
  • a system according to claim 9 wherein said means for converting said signals operates in the binary numerical system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
  • Selective Calling Equipment (AREA)
US452421A 1953-08-27 1954-08-26 Automatic switching system with reduced internal blocking Expired - Lifetime US2860189A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL332675X 1953-08-27

Publications (1)

Publication Number Publication Date
US2860189A true US2860189A (en) 1958-11-11

Family

ID=19784426

Family Applications (1)

Application Number Title Priority Date Filing Date
US452421A Expired - Lifetime US2860189A (en) 1953-08-27 1954-08-26 Automatic switching system with reduced internal blocking

Country Status (7)

Country Link
US (1) US2860189A (nl)
BE (1) BE531215A (nl)
CH (1) CH332675A (nl)
DE (1) DE1018110B (nl)
FR (1) FR1111143A (nl)
GB (1) GB787239A (nl)
NL (2) NL180933B (nl)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1021404A (fr) * 1943-08-12 1953-02-18 étage de commutation dans un système de télécommunication automatique
NL89374C (nl) * 1949-05-20

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
FR1111143A (fr) 1956-02-22
DE1018110B (de) 1957-10-24
NL180933B (nl)
NL86144C (nl)
GB787239A (en) 1957-12-04
CH332675A (fr) 1958-09-15
BE531215A (nl)

Similar Documents

Publication Publication Date Title
US3299220A (en) Programmed diagnostic equipment for a communication switching system
US3701855A (en) First idle line pickup service
GB550235A (en) Improvements in telephone systems
US2860189A (en) Automatic switching system with reduced internal blocking
US3294920A (en) Arrangement for automatic switching systems
US2911477A (en) Markers control for crossbar automatic telephone system
US1593387A (en) Telephone-exchange system
US2201573A (en) Telephone system
US3763325A (en) Main distributing frame manual switching network arrangement
US2084105A (en) Telephone control system
US3313888A (en) Split-switch crossbar trunking system
US2568101A (en) Automatic all-relay telephone system
US2761903A (en) Electrical communication systems
US2711444A (en) Junction diagram for automatic switching system
US3549815A (en) Matrix control selection system
IL27651A (en) Arrange automatic switching for telephone exchanges with indirect routing options
US3115553A (en) Automatic telephone systems
GB1178441A (en) Improvements in or relating to Communication Switching Systems.
US1601052A (en) Telephone-exchange system
US2054910A (en) Telephone system
US3271522A (en) Circuit arrangement for determining the call numbers of party line subscribers
US2573569A (en) Frame and trunk selection
US2741664A (en) Interconnecting of subscribers' lines in final selectors
US2741665A (en) Control of an automatic signalling system
US2727092A (en) Transverter